Abstract
Porous SiO 2 low-dielectric-constant films containing different porosities and sizes of pores were prepared in this study. Their mechanical properties were analyzed by a nanoindentation test. The hardness and elastic modulus of the films prepared with an ethanol molar ratio of 3 and an aging time of 16 hours reached maximum values of 2.4 and 40 GPa, respectively. With a higher ethanol ratio, the porosity increased, and the mechanical properties consequently decreased. With increasing aging time, the mechanical properties increased and then dropped due to enlarged pore sizes. The porous Si0 2 films were found to yield at an ultimate stress of 3.1 GPa, and the maximum fracture energy release rate was calculated as 3.4 J/m2. The deformation and fracture behavior was observed through crack initiation and propagation along the large amount of pores. © 2006 Materials Research Society.